704 
CAPTAIN F. W. BEECHEY ON THE TIDAL STREAMS OF 
Method of 
making the 
observations. 
Results. 
Oceanic and 
Channel 
streams. 
Mixed tides. 
in tlie water, another of these logs was occasionally sunk 12 feet, and registered 
simultaneously with the one which was 2 feet beneath the surface. 
The time of slack water, as well as the times of the cessation and commencement 
of the stream, were noted, as closely as such observations are capable of being made; 
and to render the times more certain, I have taken the mean interval between 
the time of the cessation of one stream and the time of the commencement of the 
next. The times of high water at Dover have been taken from the Admiralty Tide 
Tables, which were tested by observations made at Dover during some portion of 
the observations in the Channel, and the agreement being found sufficiently near to 
render a special register unnecessary, it was discontinued. 
All the times of observation being referred to the meridian of Dover, and compared 
with corresponding times of high and low water at that place, tables of differences 
were obtained which gave the interval between the time of slack water at each station, 
and the time of high water on the shore at Dover, and also the direction and rate of 
the stream at each hour of the tide before and after the same standard. By this 
method of comparison observations made at various periods, and even in different 
years, were brought as nearly as possible to a simultaneous record. 
To exhibit these results tables were drawn out, and twelve charts were constructed, 
showing the position of the stations and the direction of the stream at each hour of 
the tide at those places respectively, in order that the eye might at once detect the 
movement of the stream throughout both channels at any instant of time*. 
In these charts the direction of the stream is indicated by arrows, which are 
connected by curved lines empirically drawn through them ; these lines are conti- 
nuous when the water is flowing towards Dover, and broken when running in the 
reverse direction. Lastly, all those tides which have a rotatory motion are indicated 
by spirals barbed in the direction in which they revolve. 
All the observations having been subjected to this arrangement, some highly im- 
portant results were obtained. Instead of these channels having, as has been hitherto 
supposed, a stream which turns progressively later as the tide advances up the strait, 
these observations have shown that the progressive changes of stream cease at a 
certain point near the mouth of the Channel, and that beyond that spot there is a tide 
peculiar to the Channel, and quite distinct from that of the seas on either side of it ; 
so that there may be said to be two distinct streams on each side of the Strait of 
Dover, — the stream of the Ocean or outer stream, and the stream of the Channel, 
or that which is contained between the oceanic stream and the Strait of Dover. 
These streams are always running in contrary directions, and in the North Sea meet 
between the Texel and the estuary of Lynn; and in the English Channel between 
the Start and the Gulf of St. Malo. 
In the localities where these streams meet, the tide is ever varying its direction 
according as the strength of one stream prevails over that of the other ; giving to the 
* Eight of these charts only have been published. 
